Method of forming coil packages of metal foil strips

ABSTRACT

Method of forming a coil comprising a plurality of overlapping foil strips including the steps of forming a ribbon of the foil strips by bonding the strips together with an adhesive, coiling the ribbon, and then removing the adhesive.

United States Patent Cassidy et all.

[54] METHOD OF FORMING COIL PAQKAGES OF METAL FOIL STRIPS [72]Inventors: Patrick E. Cassidy; Philip S. Lowell, both of Austin, Tex.

[73] Assignees Tracor, Inc., Austin, Tex.

[22] Filed: Aug. 19, 1968 211 App1.No.: 756,729

Related US. Application Data [63] Continuation of Ser. No. 683,221, Nov.15, 1967,

abandoned.

[52] US. Cl ..29/423,156/155, 156/191 Field oiSearch ..l56/155, 157,159,191,192-193, 156/264, 266, 291, 332, 344; 29/423-424, 493

[ Mar. M, 1972 [56] References Cited UNITED STATES PATENTS 3,268,998 8/1966 Urushiyama et al ..29/423 3,436,290 4/1969 Reissner l 1 56/1931,296,934 3/1919 Drovilly ..29/423 X Primary ExaminerPhilip DierAttorney-Arnold, White & Durkee, Tom Arnold, Robert A. White, Louis T.Pirkey, John F. Lynch, Bill Durkee and Frank S. Vaden, Ill

[5 7] ABSTRACT Method of forming a coil comprising a plurality ofoverlapping foil strips including the steps of forming a ribbon of thefoil strips by bonding the strips together with an adhesive, coiling theribbon, and then removing the adhesive.

8 Claims, 3 Drawing Figures lll METHOD OF FORMING COIL PACKAGES F METALFOIL STRIPS CROSSREFERENCE TO RELATED APPLICATION The instant patentapplication is a continuation and claims priority based upon theinvention disclosed in application Ser. No. 683,221, now abandoned,entitled Method of Forming Coil Packages" filed Nov. 15, 1967 in thenames of Patrick E. Cassidy and Philip S. Lowell as inventors.

BACKGROUND OF THE INVENTION This invention relates generally to a methodfor handling material, and in particular to a method for forming coilpackages of metal foil strips.

Thin strips of metal foil, referred to as chaff, have been used as aradar counter measure since World War II. According to the EncyclopediaBritannica, aluminum foil cut into strips about half a wavelength longat the radar frequency was commonly used during World War II to givefalse echos when dispersed from aircraft. Typically, the strips are onthe order of 50 mils wide and less than 1 mil thick. The length dependson the radar frequency, which according to the Encyclopedia Britannicamay be 1 or 2 centimeters to a few meters.

At shorter wavelengths, from 1 to 20 or 30 centimeters for example, thepackaging of the foil does not present much of a problem since thestrips are relatively short. Strips less than centimeters in length arecommonly packaged in bales with the foil strips in parallel axialalignment. However, longer strips, over centimeters in length forexample, lack the axial rigidity or stiffness to be packaged in thismanner.

A novel chaff package has been devised for the longer chaff wherein thefoil strips are coiled rather than baled. In this package, the stripsare wound on the coil with each strip overlapping the succeeding strip.While the package is technically successful, hand packaging techniqueshave been too expensive to make the package economically feasible.

SUMMARY OF THE INVENTION Briefly, a long foil ribbon comprising aplurality of foil strips of the desired dimensions is formed with thefoil strips being lap bonded by a suitable adhesive. A desired coil ismade with the foil ribbon, and then the adhesive is removed by means ofa solvent, heat, or other suitable means, thus providing a coil packagecomprising a plurality of overlapping foil strips.

Typically, the metal foil is supplied in the form of a relatively wideand long sheet. In accordance with this invention, the sheet is cut intosegments equal in length to the desired length of the foil strips.Thereafter, the strips are lap bonded into a continuous sheet by theadhesive. The reconstructed sheet is then cut into ribbons of thedesired width, crimped if desired, and the ribbons are then coiled.Alternatively, the reconstructed sheet is coiled, and then a coil of thedesired width is cut from the coiled sheet. Thereafter the adhesive isremoved by solvent, heat or other suitable means.

The invention will be more fully understood from the following detaileddescription and appended claims when taken with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 11 is a perspective view of asheet of metal foil prior to processing in accordance with thisinvention.

FIG. 2 is a perspective view of segments of a metal foil sheet lapbonded together.

FIG. 3 is a perspective view of a segmented metal foil ribbon beingwound in a coil.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS Referring now to the drawingsand in particular to FIG. I, a metal foil sheet 10 is shown in thetypical form as received from a supplier. Normally, the metal foil,aluminum or other suitable material, is on the order of 4 inches wide,several hundred feet long and 1 mil or less in thickness. For ease ofhandling, the metal foil sheet is usually transmitted in a roll.

In accordance with this invention, the metal sheet is cut along thetransverse dotted lines II to produce foil segments 12 of a length equalto the desired chaff length, usually of the order of 20 centimeters orlonger.

Referring to FIG. 2, the metal foil sheet ll) is reconstructed bylapping and bonding the metal foil segments M2. No special preparationis required for the foil, but care should be taken not to get the foiloily or dirty. A suitable soluble adhesive is provided between theoverlapping portion 13 of the segments to provide the adhering bond.Such a suitable adhesive may be preferably soluble in an organic solventsuch as benzene or toluene. Alternatively, a modified methoxylatedpolyvinyl alcohol, which is soluble in water, can be used as theadhesive. The lap joint bond may be improved by the application ofpressure and/or heat depending on the type of adhesive used.

After the foil segments are lap bonded as shown in FIG. 2, the sheet iscut along the longitudinal dotted lines 15 to produce ribbons 20. Theribbons are cut to have a width equal to the desired width of the chaffstrips, typically 50 mils.

Each ribbon 20 may then be crimped to improve its axial rigidity andresiliency and then wound to produce a coil 25 as shown in FIG. 3. Thecoil 25 has an inside and an outside diameter of the desired coilpackage. Coil 25 is then supported to prevent the uncoiling of thesegments, and a solvent is applied to remove the adhesive which holdsthe segments together. Applicants have found that the soluble adhesiveis best removed by submerging the coil in an agitated container filledwith the solvent, or by passing the coil under a solvent spray. Sincemany of the materials may be beat and acid resistant, an adhesive canalso be removed by the application of heat or by a suitable acidsolution.

Thus, in accordance with this invention a chaff coil package is providedcomprising a plurality of overlapping chaff strips without the need fortime consuming manual operations or complex equipment.

While the invention has been described with reference to specificembodiments, the description is illustrative and not to be construed aslimiting the scope of the invention. Various modifications and changesmay occur to those skilled in the art without departing from the spiritand scope of the invention as defined by the appended claims.

What is claimed is:

l. The method of forming a coil containing a plurality of strips ofmetal comprising forming a segmented ribbon of said metal, the segmentsbeing bonded together by an adhesive,

winding said segmented ribbon to form a coil of desired dimensions, and

removing said adhesive from said coiled segmented ribbon.

2. The method of forming a coil :as defined by claim ll wherein saidadhesive is removed by a solvent.

3. The method of forming a coil as defined by claim l and furtherincluding the step of crimping the segmented ribbon before winding saidribbon.

4. The method of forming a coil containing a plurality of strips ofmaterial from a sheet of metal said material comprising the steps of:

cutting said sheet transversely into segments equal in length to thedesired length of said strips,

bonding said segments together with an adhesive for reconstructing saidsheet,

cutting the reconstructed sheet longitudinally into ribbons equal inwidth to the desired width of said strips,

winding each of said ribbons for forming a coil of desired dimensions,and

removing said adhesive from said coiled segmented ribbon.

5. The method of forming a coil as defined by claim 4 wherein saidadhesive is removed by a solvent.

6. The method of forming a coil as defined by claim 4 wherein thebonding of said segments includes overlapping said segments after firstapplying said adhesive to the overlapping portion of at least one ofsaid segments, and applying pressure to said overlapping portions.

7. The method of forming a coil as defined by claim 4 the overlappededge portions. wherein the bonding of said segments includes applying a8. The method of forming a coil as defined by claim 4 and modifiedmethoxylated polyvinyl alcohol to the edge portion f lnfiludirfg h PP pjeach of Said ribbons of one segment, overlapping said edge portion withthe edge fore winding 531d flbbons mt a 6011- portion of anothersegment, and applying heat and pressure to 5

2. The method of forming a coil as defined by claim 1 wherein saidadhesive is removed by a solvent.
 3. The method of forming a coil asdefined by claim 1 and further including the step of crimping thesegmented ribbon before winding said ribbon.
 4. The method of forming acoil containing a plurality of strips of material from a sheet of metalsaid material coMprising the steps of: cutting said sheet transverselyinto segments equal in length to the desired length of said strips,bonding said segments together with an adhesive for reconstructing saidsheet, cutting the reconstructed sheet longitudinally into ribbons equalin width to the desired width of said strips, winding each of saidribbons for forming a coil of desired dimensions, and removing saidadhesive from said coiled segmented ribbon.
 5. The method of forming acoil as defined by claim 4 wherein said adhesive is removed by asolvent.
 6. The method of forming a coil as defined by claim 4 whereinthe bonding of said segments includes overlapping said segments afterfirst applying said adhesive to the overlapping portion of at least oneof said segments, and applying pressure to said overlapping portions. 7.The method of forming a coil as defined by claim 4 wherein the bondingof said segments includes applying a modified methoxylated polyvinylalcohol to the edge portion of one segment, overlapping said edgeportion with the edge portion of another segment, and applying heat andpressure to the overlapped edge portions.
 8. The method of forming acoil as defined by claim 4 and further including the step of crimpingeach of said ribbons before winding said ribbons into a coil.